Predatory Bacteria

• Proteobacteria and Bacteroidetes
• Epibiotic Predators
  • Attach to surface of prey and acquire nutrients form its cytoplasm/periplasm
  • Alphaproteobacteria
• Cytoplasmic Predators
  • Invade host cells and replicate in the cytoplasm
  • Epsilopnproteobacteria
• Periplasmic Predators
  • Invade and replicate within the periplasmic space of their prey cells
  • Bdellovibrio
• Social Predators
  • Use swarming behavior to find prey, which they lyse and feed upon
  • Gammoproteobacteria and Deltaproteobacteria

Bdelllovibrio

• Small, highly mobile and curved bacteria
• After attachment to prey it penetrates the cell wall of prey and replicates in periplasmic space forming a spherical structure, bdelloplast
• Obligate anaerobe
  • Obtains energy from oxidation of amino acids and acetate
• Assimilates nucleotides, fatty acids, peptides, and even some intact proteins directly form host without hydrolyzing first
• Deltaproteobacteria are widespread in aquatic habitats

Myxobacteria

• Most complex behavioral pattern
• Formation of fruiting bodies
• Vegetative cells
  • Simple, nonflagellated, gram-negative rods that glide across surfaces and obtain their nutrients by using extracellular enzymes to lyse other bacteria and use the released nutrients
  • Excretes slime, leaving trail
  • Form swarm that exhibits self-organizing behavior
    • Allows them to behave as a single coordinated entity in response to environmental cues
  • Exhaustion
    • Vegetative cells migrate toward each other
    • Aggregation is mediated by chemotactic or quorum-sensing
    • Myxospores
      • Resistant to drying, UV radiation, heat(endospore more resistant)
    • Fruiting bodies
      • Masses of myxospores embedded in slime, or complex, consisting of stalk and heads
      • Stalk composed of slime
      • Majority of cells migrate to head where they undergo differentiation into myxospores